交易后从PayPal获取信息

I want to create a simple transaction on my Web Site where after the person's transaction completes, I want paypal to redirect the user to go to a place on my site and I want PayPal to provide me with details so I can use PHP to parse it and email them the link to their purchase. I'm not sure what notify_url does? ThanksI want to create a simple transaction on my Web